1. Field of the Invention
The present invention refers to an automatic discharge valve for liquids, especially for use in waterclosets, that does not suffer from the hydraulic knock-down in sudden discharges of a body of water. Especially, the present invention refers to a valve apt to be used at different pressures of water, from 0.15 to 7 atmospheres, approximately, that is, at the pressures normally found in urban sanitary installations.
More particularly, the present invention refers to a novel combination of improvements incorporated in such valves.
2. Description of the Prior Art
U.S. Pat. No. 2,868,492 granted on Jan. 13, 1959 to Vittorio Volcov and Nicolas Baranoff discloses an automatic discharge valve for liquids that does not suffer from hydraulic knock-down and is apt to be applied in urban sanitary installations within the range of pressures usual in such installations. The principal novelty of this patent consists in the provision of a damping chamber within the discharge valve, which absorbs the pressure formed upon closure and thereby eliminates the water-hammer. The correct operation is obtained with the aid of elastic sealing means, comprising a cylindrical rubber piston with a plurality of rings at its circumference allowing a full fit in the sealing.
As a further development of this novel idea, applicant obtained on Oct. 20, 1964 Argentine Pat. No. 141,444 which permits the elimination of the elastic body 11 in the damping chamber 10 of the said U.S. patent, without losing thereby the advantages offered by U.S. Pat. No. 2,868,492.
Said Argentine Pat. No. 141,444 describes a valve of the above mentioned type comprising two bodies provided with hollow spaces separated from each other by a circular diaphragm, the central portion of which normally seals an inlet conduit for water which, jointly with the discharge conduit for water, opens into one of the hollow spaces, the other one of the hollow spaces being connected by means of respective channels, provided with flow restrictors, one to the water inlet and the other one to the water outlet, the channels crossing the peripheral zone of the diaphragm.
It has been discovered that upon entering into this valve the water carries along particles such as those that might be introduced into the storage tank when same is cleaned by personnel wearing boots, or particles entering in any other way, and some of these particles penetrate into the channel provided with a flow restrictor connected with the inlet for water, getting as far as the corresponding flow restrictor and further restricting its section. This reduction of the section of the flow restrictor affects the operation of the valve causing the closure time of the inlet conduit to be longer than it should be which in turn results in an unnecessary loss of water and in an excessive protraction of the interval in which the valve may be used for the next discharge. In the worst case a total obstruction of the flow restrictor may ensue, and then the valve becomes inoperative until such time as it has been disassembled in order to eliminate obstruction, which operation, as a rule, is not within the scope of persons not specialized in this type of valve.
It has been discovered that upon actuating the lever arm causing the discharge of water, between the piston of the plug (which normally seals the communication between the hollow space in which it is situated and the discharge conduit) and the nozzle in which it is situated, a water leak is caused, as at this point it is not possible to place a plug, inasmuch as it is, at the same time, the air inlet into the hollow space. This leak of water causes an ugly appearance outside the valve.
It has been discovered that the diaphragm described and illustrated in U.S. Pat. No. 141,444 suffers from certain drawbacks and therefore certain alterations have been made in same which constitute the novelty of this invention and consist in giving a conical shape to the portion of the diaphragm comprised between the circumferential edge compressed by the two bodies comprising the valve and its central thickening; providing this circumferential edge with radial fingers enabling a better centering and giving an increased thickness to the portions of the circumferential edge at points corresponding to the passage of fluid supply and discharge conduits, increasing thereby the pressure in the hollow space opposite the one carrying the supply and evacuation conduits for discharge water; providing a concavity at its center for a better seating of the central portion of the supply conduit for discharge water; and surrounding this concavity with a reinforcement ring.
Finally, it has been discovered that when manufacturing from plastic material the two bodies which, in assembled condition, form the valve, due to properties of the plastic material, not all the surfaces that should be flat are really so, especially those surrounding perforations having a small diameter in which shrink-holes may appear making them slightly conical. Such tapers prevent a tight sealing.